James recently contacted Athena Energy about installing solar in his home. His question was about the cost/benefit of a stand-alone system. Here is my reply
Good to hear from you! I would be happy to answer your question about cost/benefit. As you know solar panels have gotten cheap enough that you can buy from places like sunelec.com for $0.38/W. If you add qty(4) 220W panels to our basic ASI-1000 grid-tie system then you will have about 700W AC output for several hours/day. This will get you about 1 MWhr of energy per year or about $300. The return on investment will be about 4-5 years, then factor in the federal rebate and your return on investment could go down to 3 years.
For homes that operate completely off-the-grid you need to add the extra cost of a transfer switch and batteries to the equation. We recommend a transfer switch because there may be situations where you need to supplement power with a generator. Our system mates well with the very popular Honda 2000i. So a totally off-grid home will have the added expense of batteries (about $1000) and a generator (another $1000). This extra expense will put the power system up at about $5000. The benefits of such a system are complete autonomy but it would take at least 10 years to make a payoff. In certain situations you can factor in the cost savings of not having to pay the utility to bring power to a remote home.
Hope this helps!
Dimos at Athena Energy.
The posted photo is the living room of an off-grid summer home with a 400W solar panel system being upgraded to 800W